This invention relates to an exercise device or system that incorporates a rotating member for resisting input forces applied by a user, and more particularly to a resistance control arrangement for use in such an exercise device or system.
Many exercise devices utilize a rotating member that rotates in response to the application of input power by a user. In an exercise device of this type, it is common to provide resistance to rotation of the rotating member in order to provide resistance to the user. One example of an exercise device that incorporates a rotating member is a bicycle trainer, which includes a frame that supports the bicycle and a roller that engages the driven wheel of the bicycle. The rotating member may be in the form of a flywheel that is interconnected with the roller, and that rotates in response to rotation of the roller caused by rotation of the bicycle wheel. Another example of an exercise device that incorporates a rotating member is a stationary exercise cycle, which includes a frame having a seat and handlebars that support a user, in combination with a flywheel that is driven into rotation by operation of a pedal and chain assembly.
In a typical rotating member-type exercise device or system, a brake arrangement is used to resist rotation of the rotating member such that the rotating member presents a load in watts. The brake arrangement can be any type of brake, such as a magnetic or mechanical brake. In an electronic exerciser that incorporates a resistive load system, the resistors are modulated between ON and OFF states to brake the rotating member. The degree of resistance to rotation of the rotating member is typically controlled by the user, either manually or automatically. In a manual control system, the user selects a resistance setting and the brake arrangement is responsive to the user-selected setting to establish the resistance level. Changes in the level of resistance are accomplished during an exercise session by manually selecting desired settings at different times in the session. In an automatic system, the user selects a program and the resistance level is automatically varied during an exercise session to adjust resistance according to the program.
In the past, e.g. in a magnetic eddy current resistance unit, the position of one or more movable magnets relative to the rotating member is detected, and a lookup table is used to calculate resistance. In such a system, the various parameters are inputted into a controller, to calculate resistance based on magnet position. Systems of this type are functional but are highly inaccurate due to numerous variables that are involved in manufacture, assembly, engagement with the bicycle wheel (in the case of a bicycle trainer), and in operation of the power input system and the resistance unit. This type of system is “open”, in that the system is first calibrated to correlate the magnet position to power, and the controller then alters the positions of the magnet(s) to provide a desired braking force according to the lookup table to create the desired load. The numerous variables significantly limit the accuracy of a system of this type.
In the case of an electronic resistance unit, the controller functions to control the duty cycle of the resistors, which controls the load experienced by the user. The duty cycle, in turn, is calibrated such that a certain duty cycle is determined to correspond to a certain load. Again, this is an open system, in that there is no actual measurement of power. The measurement is done in a laboratory to create the lookup table, and when a product is sold the same lookup table is used on all products. Due to the numerous process variations and other variables as noted above, it has been found that systems of this type have accuracy limitations on the order of 15-20%.
It is an object of the present invention to provide a rotating member resistance unit that includes the ability to control a user's power level in response to the degree of resistance applied to the rotating member. It is another object of the present invention to enable a user to monitor his or her own power output, and to control the applied resistance to provide a desired power output. Yet another object of the present invention is to provide control of the braking force that resists rotation of a rotating member in an exercise device resistance unit, regardless of the form of the braking mechanism. A further object of the invention is to measure and control the resistance applied to a rotating member in a resistance unit, which is used in combination with a desired power curve that may either be pre-programmed or inputted by the user, to enable a user to accurately achieve a desired power output.
In accordance with one aspect, the present invention contemplates an exercise system including a user input arrangement, a rotatable member that rotates in response to an input force applied by a user on the user input arrangement, and a power sensing arrangement configured to sense power applied to the rotatable member due to the input force applied by the user. The exercise system further includes a variable resistance arrangement interconnected with the power sensing arrangement and with the user input arrangement. The resistance arrangement is operable to apply resistance to rotation of the rotatable input member, and is variable in response to the power sensing arrangement to vary the resistance applied to the rotatable input member. The variable resistance arrangement may be in the form of a brake arrangement that interacts with the rotatable member to resist rotation of the rotatable member, and to thereby resist the input force applied by the user. The variable resistance arrangement includes a controller for controlling the brake arrangement in response to the power sensing arrangement. The power sensing arrangement is in the form of a resistance measuring arrangement for measuring the degree of resistance to rotation of the rotating member applied by the brake arrangement, to determine the power applied by the user to rotate the rotatable member.
The power sensing arrangement may also be in the form of a rotatable power sensing member interposed between the user input arrangement and the rotatable member. The rotatable power sensing member is preferably rotatable about an axis of rotation that is concentric with an axis of rotation about which the rotatable member is rotatable. Representatively, the power sensing member may be in the form of a power sensing hub member to which the rotatable member is mounted.
The rotatable member may be the wheel of a bicycle, and the resistance arrangement may be associated with a bicycle trainer that supports the bicycle. In this embodiment, the bicycle wheel is engaged with a roller that is interconnected with the resistance arrangement. The power sensing arrangement is carried by the bicycle, and senses power applied by the user on the user input arrangement for imparting rotation to the bicycle wheel. The power sensing arrangement is in the form of a power sensing hub to which the bicycle wheel is mounted. In another embodiment, the power sensing arrangement is associated with the bicycle trainer and senses power applied by the bicycle wheel for imparting rotation to the roller.
The rotatable member may also be in the form of a flywheel associated with an exercise cycle, in which the resistance arrangement acts on the exercise cycle flywheel to resist rotation of the exercise cycle flywheel. The power sensing arrangement may be in the form of a power sensing hub to which the flywheel is mounted. The power sensing arrangement may also be in the form of a resistance measuring arrangement for measuring the degree of resistance to rotation of the flywheel applied by the brake arrangement, to determine the power applied by the user to rotate the flywheel.
The invention also contemplates a method of controlling operation of a resistance arrangement incorporated in an exercise device or system, in which the exercise device or system includes a rotatable member that rotates in response to a user-applied input force, substantially in accordance with the foregoing summary. The invention further contemplates a resistance arrangement, also in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.